Fiber laser apparatus and method for processing workpiece

2. The method of claim 1 further comprising repeating the steps (a) through (d) to further process the column of the p-Si film until a desired grain size and orientation of p-Si has been obtained, wherein the desired scanning velocity Vscan and beam intensity profile are controlled so that a thermal reaction of each spot creates a completely melted triangularly-shaped film area with an apex which is spaced from the spot in a counter-scanning direction at a length Lm at least 10 times greater than the width Ws, and the distance dy varies between 0.025Ws to Ws and increases within the range as a repetition rate of formation of the consecutive scanned stripes increases to prevent p-Si grains from degradation and physical destruction of the a-Si film due to feedback overheating.

4. The method of claim 3, wherein displacing the panel in the scanning direction at the distance dx of at most 0.5 mm precludes visible Mura, and the distances dy and dx are selected to be equal to one another or different from one another but the product dx*dy at each location is constant.

6. The method of claim 1 further comprising shaping of the sub-beam in each of the scanning and cross-scanning directions, thereby having the desired spatial intensity profiles in respective scanning and cross-scanning directions.

7. The method of claim 1 further comprising controlling polarization of the sub-beam incident on the film, thereby controlling alignment of the polycrystalline grains such that the polarization of the sub-beam incident on the film is set perpendicular to the spot beam scanning direction, thereby controlling alignment of the polycrystalline grains.

8. The method of claim 1, wherein the beam is single mode or multimode in a ultraviolet (UV) wavelength range.

10. The method of claim 9, further comprising generation of a plurality of RFs at the input of the AOD, and adjusting amplitudes of respective RFs to alter the divergence of sub-beams in the cross-scanning direction, thereby providing a desired intensity profile across the stripe, the intensity profile being selected from Gaussian, super-Gaussian or flat-top.

11. The method of claim 1, further comprising mounting deformable optics between the scanner unit and the panel such that a focus plane tracks the panel surface, the deformable optics including one or more deformable mirrors, each of which have a continuously variable radius of curvature along a length of the sub-beam and along a length of each mirror of the polygon to compensate for an unevenness of the panel surface.

13. The apparatus of claim 12, wherein the QCW fiber laser operates with a duty cycle of at most 100% outputting the laser beam in a single mode or multiple transverse modes, whereby when operated at a duty cycle below 100%, the QCW fiber laser outputs a train of nanosecond pulses at a regular pulse repetition frequency from 80 to 200 MHz, which generates a thermal response of the treated surface identical to that caused by the beam from the QCW fiber laser operated with a 100% duty cycle.

15. The apparatus of claim 14, further comprising a power controller located downstream from the pre-scan beam conditioner and coupled to the polarizer so as to adjust the constant power if it deviates from the predetermined power.

16. The apparatus of claim 12, further comprising multiple QCW fiber lasers outputting respective laser beams incident on the pre-scan beam conditioner, which is configured with a beam combiner configured to output the laser beam having the desired intensity profile in the scan direction, cross-scan direction, or scan and cross-scan directions, wherein the desired intensity profile is selected from the group consisting of a Gaussian, super-Gaussian, flat top profile, and combinations of these profiles.

19. The apparatus of claim 18, wherein the post-scan optical assembly, including the spherical imaging lens, a cylindrical imaging lens and an anamorphic imaging lens, further includes one or more cylindrical lenses located downstream from the objective lens, which functions to adjust the spot beam in the cross-scan direction.

20. The apparatus of claim 12, wherein the multi-axis stage is configured to continuously move the workpiece in the cross-scan direction at a m/sec speed and over a distance dy not exceeding a full width of the stripe to form the column and operative to displace the workpiece in the scan direction at a distance dr at most equal to a width of the column, wherein the distances dy and dx are selected to be equal to one another or different from one another but the product dx*dy at each location is constant.

21. The apparatus of claim 20, wherein the distance between adjacent stripes in the cross-scan direction and distance between adjacent columns are selected such that each location of the processed surface is irradiated in a range from 10 to 40 times.

22. The apparatus of claim 12, further comprising deformable optics between the scanner and the workpiece configured to compensate for an unevenness of the surface.